How the Microscope Challenged Vegetarianism

A rescued chicken named Cherry eats vegetables and cakes during a lunch event held by animal rights activist group People for the Ethical Treatment of Animals (PETA).Jason Lee / Reuters

The ideal of a non-violent diet goes back to the origins of most world religions. Adam and Eve’s prelapsarian diet was plant-based, while in the East, Hinduism, Buddhism, and Jainism all embraced the concept of ahimsa, or non-violence toward living things—even if many Hindus and Buddhists aren’t necessarily vegetarian themselves. We speak with author Colin Spencer, Gastropod listener and Jain Purvi Shah, and theologian Jo Ann Davidson to understand the genesis of these beliefs and their evolution throughout human history.

In the 1600s and 1700s, new scientific discoveries were employed to adjudicate the question of whether eating meat was morally wrong: Author and activist Tristram Stuart explains that, while vegetarian advocates held up the similarity of human and animal nervous systems to condemn the suffering inflicted by meat-eating, their opponents used the newly invented microscope to demonstrate that even the most rigorous Jain is still killing untold quantities of microbial and insect life every time they sit down to dinner. Today, the debate over animal rights and an animals role as a potential source of food still rages.

But the claims that giving up meat will reduce heart attacks and save the planet—they must be much easier to prove, right? Not so fast: We speak to nutritionist Frankie Phillips, epidemiologist Corinna Koebnick, rancher Nicolette Hahn Niman, and researchers Gidon Eshel and Marco Springmann to understand the science behind a meat-free diet’s reported health and environmental benefits—and figure out its flaws. As we discover this episode, nothing about eating meat or not eating meat is as clear cut as it seems.